Armoring for mill drums or the like



July 18, 1961 H. TAUBMANN ETAL 2,992,732

ARMORING FOR MILL DRUMS OR THE LIKE Filed Nov. 12, 1959 M MW ARMORING FOR NIHJL DRUMS OR THE LIKE Harro Taubmann, Niederhochstadt (Taunus), and Johann Oberndiirfer, Oberursel (Taunus), Germany, as-

signors to Fellner & Ziegler G.m.b.H., Frankfurt am Main West, Germany Filed Nov. 12, 1959, Ser. No. 852,450 Claims priority, application Germany Nov. 19, 1958 3 Claims. (Cl. 241-182) The present invention relates to mill drums and is particularly concerned with the arrangement of armor plates or lining in the drums of tube mills used for crushing very hard materials.

Tube mills or the like which are primarily intended for crushing hard materials are lined on the inner surface thereof with armor plates. Heretofore it has been the general practice to connect these armor plates with the drum casing of the mill by means of threaded bolts. For this purpose the drum casing is provided with a suflieient number of bores through which the threaded bolts on the armor plates extend and to secure the plates rigidly to the drum casing by means of nuts threaded onto the outwardly extending bolts.

It has already been proposed to obviate the mounting of the individual armor plates on the drum casing by means of bolts by providing the armor plates along their longitudinal side planes which extend parallel to the center axis of the drum with recesses which, together with complementary recesses on adjacent plates, form cavities or apertures adapted to receive intermediate coupling members. Such coupling members may be in the form of cylindrical rods or pins. As the rods or pins are driven into the hollow spaces the armor plates are rigidly fastened or anchored with respect to the inner casing surface.

This manner of anchoring involves considerable shortcomings. The exact or accurate fitting of the armor plates onto the inner casing surface in itself introduce difiiculties because it is difllcult to make the proper allowances for the inevitable inaccuracies incident to the casting of the armor plates. Furthermore, there arise considerable temperatures during the operation of the mill which result in heat expansion of the plates which can lead to very cumbersome operating difficulties in mills having the armor plates mounted in accordance with the old means, such as the cylindrical rods or pins. Also the hammering elfect of the charge of material to be milled on the inner surface of the armor plates has adverse effects on the fastening means known heretofore.

It is therefore an object of the invention to eliminate the mounting of the armor plates by means of bolts extending through the drum casing of the mill while providing secure and reliable internal anchoring of the armor plates in such a manner as to eliminate interruptions in operation resulting either from inaccuracies in the casting of the armor plates, by heat expansion due to hammering or knocking of the charge in the mill, or other causes.

In accordance with the invention, adjacent armor plates are placed onto the inner surface of the drum casing with a space or gap therebetween and intermediate coupling members are inserted in the spaces between adjacent armor plates, which are resilient laterally of their longitudinal extent. The intermediate coupling members may be in the form of cylindrical coil springs having an outer diameter which is greater than the width of the recesses of any two adjacent armor plates together with the gap between said plates. It is also possible to employ slotted tubes in lieu of such coil springs, or to insert a pair of undulated strips adjacent each other in the hollow space between proximate armor plates in a manner to insure a resilient effect of the intermediate members transversely of their longitudinal extent.

States Patent Patented July 18, 1961 As a result, if in the arrangement in accordance with the invention there exist casting inaccuracies in the armor plates, or heat expansion of these plates occurs, these conditions are compensated for by the resilient elfect of the intermediate members disposed between adjacent armor plates.

In accordance with the invention it is not necessary to provide such coupling members which are resilient transversely of their longitudinal extent between all of the a-rmoring plates of the tube mill or the like. It is sufficient, depending on the diameter of the drum of the mill to provide individual resilient coupling members circumferentially of the mill while the remaining coupling members may be rigid, for example, they may be cylindrical rods or pins. The unimpeded and satisfactory operation of the mill is nevertheless insured with the characterizing features of the invention. The small gap between the individual armor plates does not interfere with the operation of the mill.

Further details and objects of the invention will become apparent from the following description. of an embodiment of the invention with reference to the accompanying drawings in which FIG. 1 is a section of the wall of the drum casing of a tube mill having a lining of armor plate taken transversely with respect to the longitudinal axis of the mill.

FIG. 2 illustrates in detail and to a larger scale the connection between two armor plates with a helical spring interposed.

The armor plates 2, 3, 4 and 5 are disposed on the inner wall of the drum casing 1 in a manner that small gaps 6, 7, 8 are provided between the adjacent plates which may be approximately 1 or 2 mm. in width. Substantially semi-circular recesses are provided along adjacent sides of the plates 2 and 3 into which cylindrical pins 9, 10 are placed. The diameter of these pins is such that the small gaps 6, 7 are maintained between the plates. The plates are provided with inwardly bulging conformations at the ends adjacent said gaps.

Intermediate plates 4 and 5 the gap 8 is provided which may be somewhat wider than the gaps 6 and 7. The cylindrical space 11 between the armor plates 4 and 5 is provided with a cylindrical helical spring 12. The outer diameter of this spring 12in relation to the inner diameter of the cylindrical opening 11 is such as to provide the gap 8 between the two armor plates 4 and 5.

In this manner secure engagement of the armor plates with the inner surface of the drum casing is insured without the armor plates being fastened to the drum casing by means of threaded bolts which extend through the casing, and secure fastening of the plates relative to one another is insured. Nonetheless, all inaccuracies of the armor plates can be compensated for by the arrangement of the gaps between the plates into which the intermediate coupling members are placed. In this manner the heat expansion a swell as hammering effect of the charge of material being ground cannot adversely affect the secure mounting of the armor plates on the inner wall of the drum casing in the mill.

Having now described our invention in connection with the embodiment illustrated in the drawings, we do not wish to be limited thereto but what we desire to protect by Letters Patent of the United States is set forth in the appended claims.

We claim:

1. Armoring for the drums of tube mills or the like of the type comprising a generally cylindrical drum casing and a plurality of armor plates disposed along the inner drum wall and extending in the direction of the drum axis, said plates having adjacent inwardly bulging end portions of increased thickness and presenting lateral surfaces having recesses, said recesses of adjacent said plates registering and defining an aperture for an intermediate member therebetween, adjacent said plates being positioned with a gap therebetween, and at least one resilient intermediate member in the form of a helical spring disposed in one said aperture intermediate adjacent plates, said spring being compressible transversely of the longitudinal extent of said plates and yielding to heat expansion of said plates.

2. Armoring for the drums of tube mills or the like of the type comprising a generally cylindrical drum casing and a plurality of armor plates disposed along the inner drum wall and extending in the direction of the drum axis, said plates having adjacent inwardly bulging end portions of increased thickness and presenting lateral surfaces having recesses, said recesses of adjacent said plates registering and defining an aperture for an intermediate member therebetween, adjacent said plates being positioned with a gap therebetween, and at least one resilient intermediate member disposed in one said aperture intermediate adjacent plates, said intermediate member being in the form of a helical spring having in non-compressed condition a greater diameter than the diameter of adjacent recesses and being operative to force adjacent plates apart to press them against other plates and provide for firm engagement of said plates with each other and with said drum.

3. Armoring for the drums of tube mills or the like of the type comprising a generally cylindrical drum casing and a plurality of armor plates disposed along the inner drum Wall and extending in the direction of the drum axis, said plates having adjacent inwardly bulging end portions of increased thickness and presenting lateral surfaces having recesses, said recesses of adjacent said plates registering and defining an aperture for an intermediate member therebetween, adjacent said plates being positioned with a gap therebetween, and at least one resilient intermediate member in the form of a helical spring or the like disposed in one said aperture intermediate adjacent plates, and rigid intermediate members in the form of solid rods disposed in the apertures between said adjacent plates and the plates adjacent thereto, said resilient intermediate member being compressible transversely of the longitudinal extent of said plates to yield to forces of heat expansion in adjacent plates while pressing them against said rigid intermediate members and the plates proximate said adjacent plates.

References Cited in the file of this patent UNITED STATES PATENTS 939,637 Rotherham Nov. 9, 1909 1,772,026 Bartley Aug. 5, 1930 FOREIGN PATENTS 399,990 Germany Aug. 11, 1924 

